Fuel nozzle



De@ 6, 1960 w. G. JAcoBlTz ET AL 2,963,282

FUEL NozzLE Filed May 2, 1957 ,gf-gz INVENTORS rg/ f States FUEL NOZZLEFiled May 2, 1957, Ser. No. 656,719

2 Claims. (Cl. 261-4) The present invention relates to an atmospherictype fuel nozzle for a fuel injection system. More particularly, thisinvention is an improvement over the atmospheric nozzle shown anddescribed in copending application Serial No. 512,175, Homfeld et al.,filed May 31, 1955, now abandoned.

Atmospheric fuel nozzles of the type shown in the aforenoted copendingapplication have presented a problem in actual use in that it has beendifficult to provide a set of such nozzles with uniform flowcharacteristics. These atmospheric nozzles involve the use of extremelysmall orifices as a consequence of which any slight variation in size orconfiguration of an orifice can perceptibly alter the flow through thenozzle as compared with another nozzle used in the same system. Theobvious result of these varying flow characteristics is an unevendisposition of fuel to the various cylinders of the engine. On the otherhand, for the sake of economy of manufacture it has not been feasible toutilize nozzles having identical flow characteristics. As a consequence,it has been necessary to compromise and utilize nozzles within a givenbut theoretically undesirably large range of flow characteristics. Theinability to produce in commercial quantities more acceptable nozzlesled to the development of the present nozzle construction.

The present atmospheric nozzle represents an improved constructionwhereby atmospheric nozzles may be economically manufactured in a waywhich will insure that the flow characteristic of the nozzles will bemuch more uniform than has heretofore been possible.

To achieve this end, the present atmospheric nozzle is of a fabricatedor built-up design in which the critical or fuel metering orifice isformed in a separate easily worked upon element which has enabledgreater uniformity of nozzle flow and, further, which permits thesalvaging of the major portion of the nozzle in the event the fuelorifice requires replacement.

It is also an object of the present invention to provide an atmospherictype nozzle in which it is possible to achieve a much more uniform owversus pressure curve and further which curve has the characteristic ofan orilice meter. The orifice meter type ow curve is desirable in thatit insures a slight enrichment at idle or low fuel ows. On the otherhand, the previous type atrnospheric nozzles have a characteristic owcurve similar to a venturi meter as a consequence of which they havetended to lean out fuel ow under idling conditions which is undesirable.

The present nozzle provides the fuel metering orifice in a thin platemember which is clamped in axially spaced relation to the atmosphericmetering orifice and which orifice plate in addition to providing muchimproved ow characteristics results in a better targeting of the fuelstream through the atmospheric metering nozzle than has been achievedwith the earlier designs.

In view of the small orifice sizes utilized in such atmospheric nozzlethe problem of clogging has been extremely serious. With the presentnozzle it has been possible arent lC) to combine a fuel filter therewithin such a way as t0 insure non-clogging operation of the orifices.

The details and other objects and advantages of the subject nozzle willbe apparent from the description which follows.

In the drawings:

Figure 1 is a sectional view of the subject atmospheric nozzle;

Figure 2 is a fragmentary enlargement showing the nozzle in greaterdetail; and

Figure 3 is a modified lter configuration.

In general the atmospheric nozzle functions in the same manner as setforth in the aforenoted Homfeld application. Briefly, the nozzleincludes a fuel inlet passage 10 formed in a member 12 which is adaptedto ow fuel through a fuel metering orifice 14 across a relatively largeatmospheric passage or space 16 formed in a member 18 and target thefuel stream through a relatively larger orifice 20 in member 18. Theorifice 20 is of such a size as to meter the quantity of air flowingtherethrough but to have no metering effect on the fuel stream. The airmetering orifice 20 communicates with an enlarged passage 22 in thelower end 24 of nozzle member 18 and which end is adapted to suitablyproject within the induction passage leading to a cylinder of theengine.

As described in detail in the copending Homfeld application thereference air space 16 normally communicates with the atmosphere and inthis way isolates the fuel metering function from variations in manifolddepression which are acting on end 24 of the nozzle member 18. In thisway fuel supplied through orifice 14 is adapted to be accuratelycontrolled by suitable forces elsewhere inthe injection system.

In the past the fuel nozzle has either been of an integral constructionas a consequence of which any intolerable variations in the size of thefuel metering orifice has resulted in the complete loss of the entirenozzle or a major part thereof. In other types sof atmospheric nozzlesthe orifice may have been formed in a member detachable from the entirenozzle but in all instances the orifices have been formed in relativelylarge members which have been difficult to accurately machine and,further, which in the event of a defective nozzle have still meant thereplacement of a considerable portion of the entire nozzle. To overcomethese disadvantages and insure more uniformly functioning nozzles,supra, the present nozzle is fabricated from a plurality of parts insuch a way that the component containing the fuel metering orifice iscapable of easy handling, accurate machining as well as simplereplacement at very little cost.

In the present device member 12 includes axially spaced threadedportions 26 and 2S on the exterior surface thereof. Fuel passage 10formed in member 12 includes a relatively large orifice 30 intermediatethe ends thereof which performs an initial fuel metering function.

Member 18 includes an internally threaded bore 32 which terminates in arelatively large orifice 34 in open communication with the transverselyformed atmospheric air passage 16. The air metering orifice 20, asalready described, is axially aligned and spaced from fuel meteringorifice 14 and communicates with the enlarged fuelair mixture passage22. i

The threaded portion 28 of member 12 is adapted to be threaded within.bore 32 of member 1S. A plate member 36 is disposed within anon-threaded portion 3S of bore 32 and positioned therewithin. To insureproper radial alignment of the fuel metering orifice 14 formed in plate36 with orifices 20 and 34, the plate or disc 36 is substantiallyradially coextensive with bore portion 38. The inner end of member 12terminates in a cylindrical sleeve portion 40 which is adapted toaxially clamp plate 36 within the bore portion 38 and make a completeatmospheric nozzle assembly.

As thus far described, it will be apparent that the relatively largeorifices or restrictions 20, 30 and 34 are formed in the large members12 and 18. These orifices, being considerably larger than the fuelmetering orice 14, are more easily machined and do not have to bemaintained to the same degree of accuracy required of the fuel meteringorifice.

On the other hand, the fuel metering orifice 14 is formed in arelatively thin circular disc or plate 36 which may be easily drilledand if formed beyond tolerable limits may be disposed of with relativelylittle loss. To illustrate the manufacturing advantage of using orificeplates it may be appreciated that a stack of such plates, at leastconsisting of those to be utilized in the same system, may be clampedtogether and drilled as a unit insuring substantial uniformity offormation. In addition to the inherent advantage of utilizing an orificeplate to provide the desired fuel iiow characteristics through thenozzle, the ability to commonly form a plurality of such orifices, asdescribed, further insures that the range of fiow characteristicsbetween the nozzles in a given system will be held to an absoluteminimum.

To better appreciate the economy realized by the present construction,it is Well to note that the plate 36 is in the nature of .005 of an inchthick. In addition to insuring uniformity of orifice formation, it isapparent that with discs of such thinness it is preferable that they bedrilled in a stack for mutual reinforcing purposes. Further, in assuringgreater flow uniformity is has been found advantageous to fiow fuelthrough the orifices in the same direction in which they were drilled.For this purpose it is possible to suitably mark, as by vapor blasting,one side of the plate from which the discs are formed to insure thatthey will be assembled within the nozzle in the right direction.

The fabricated construction of the present nozzle has made it possibleto conveniently incorporate a filter element proximate the fuel meteringorifice 14 where such location was not feasible with earlier types ofconstruction. To this end, a preferably metal mesh filtering element 42having a radial fiange 44 is adapted to be clamped between the orificeplate 36 and the sleeve portion 40 of member 12'. In order to rigidityand thereby strengthen the filtering element an annular U-shaped rim 46is clamped about the filter fiange 44, In this way as the member 12 isthreaded within the member 18 the metal rim 46 supports the filterelement 42 and facilitates clamping of the orifice plate 36 within thebottom of bore portion 38.

The filter element may be of various configurations as the conicalversion of Figures 1 and 2. However, for reasons of strength and ease offormation, the dome shaped filter element 43 of Figure 3 has been foundto be preferable. In this case a ange 44 and rim 46 are still provided.

It is apparent that the present nozzle construction is such that eitheror both the orifice plate 36 and the filtering element 42 or 48 may beeasily replaced in the event either becomes defective for any reason.

We claim:

1. A fuel injection nozzle comprising a plug member having a fuel inletin one end thereof and a longitudinal fuel passage therein, an openended tubular sleeve portion on the other end of said plug member, afuel metering orifice of reduced diameter in said longitudinal fuelpassage intermediate the ends of said plug member, socket retainingmeans on said plug adjacent said tubular sleeve portion, a socket memberhaving a longitudinal passage therethrough, plug member engaging meansin one end of said longitudinal passage of said socket member tocooperatively accommodate said socket retaining means on said plugmember, a portion of said longitudinal passage of said socket memberextending longitudinally from said plug member engaging means, a seatterminating said portion and extending radially inwardly thereof, afurther portion of said longitudinal passage of said socket memberextending longitudinally from said seat and defining a fuel inletorifice and communicating with a transverse air passage, an air-fuelorifice formed in the other end of said longitudinal passage of saidsocket member and coaxially aligned with said fuel inlet orifice andextending from said air passage, a thin disc member removably retainedon said seat by said tubular sleeve portion, a fuel metering orifice insaid disc formed by a hole drilled from the inlet to the outlet side ofsaid disc member, and said fuel metering orifice in said disc memberbeing aligned and spaced from said air-fuel orifice to direct fuelthereinto through said air passage.

2. A fuel injection nozzle comprising a plug member having a fuel inletin one end thereof and a longitudinal fuel passage therein, an openended tubular sleeve portion on the other end of said plug member, afuel metering orifice of reduced diameter in said longitudinal fuelpassage intermediate the ends of said plug member, socket retainingmeans on said plug member adjacent said tubular sleeve portion, a socketmember having a longitudinal passage therethrough, plug member engagingmeans in one end of said longitudinal passage of said socket member tocooperatively accommodate said socket retaining means on said plugmember, a portion of said longitudinal `passage of said socket memberextending longitudinally from said plug member engaging means, a seatterminating said portion of said longitudinal passage of said socketmember and extending radially inwardly thereof, a further portion ofsaid longitudinal passage of said socket member extending from said seatand delining a fuel inlet orifice and communicating with a transverseair passage, an air-fuel orifice formed in the other end of sa'dlongitudinal passage of said socket member and being coaxially alignedwith said fuel inlet orifice and extending from said air passage, a thindisc member removably retained on said seat by said tubular sleeveportion, a fuel metering orifice in said disc member aligned and spacedfrom said air-fuel orifice to direct fuel thereinto through said airpassage, a filtering element disposed within said tubular sleeve portionand having a radially outwardly extending fiange portion, and an annularrim surroundedly fixed to said fiange and adapted to be clamped betweensaid disc member and said tubular sleeve portion.

References Cited in the file of this patent UNITED STATES PATENTS2,210,846 Aghnides Aug. 6, 1940 2,316,832 Aghnides Apr. 20, 19432,420,795 Phillips May 20, 1947 2,483,951 Watson Oct. 4, 1949 2,511,213Leslie June 13, 1950 FOREIGN PATENTS 944,697 Germany June 21, 1956527,491 Belgium Apr. l5, 1954

